Soluble Interleukin-2 Receptors in the Sera of Patients With Hairy Cell Leukemia: Relationship With the Effect of Recombinant α-Interferon Therapy on Clinical Parameters and Natural Killer In Vitro Activity

In this study we provide evidence that the sera of patients with hairy cell leukemia (HCL) contain a factor that can prevent the binding of a monoclonal antibody specific for interleukin-2 receptor (IL-2R) to its target. This factor corresponds to the soluble form of IL-2R (slL-2R), as assessed by a specific enzyme-linked immunosorbent assay test, and appears to be released by neoplastic hairy cells. The serum sIL-2R levels were very high at diagnosis and significantly reduced during recombinant α-interferon (rIFNα2) therapy. Values of slL-2R appeared to be inversely related to the natural killer in vitro function displayed by peripheral blood mononuclear cells from the same patients. The presence of slL-2R in the serum of patients with HCL might be involved in the impairment of cell-mediated immunity observed in these patients and could represent a valuable marker for monitoring different phases of the disease and for modulating IFN therapy. © 1987 by Grune & Stratton. Inc.